LONG-TERM WARFARIN USE MAY INCREASE RISK OF FRACTURES IN MEN

Author: Anna D. Garrett, PharmD, BCPS, CPP

A study of Medicare beneficiaries with atrial fibrillation who
were hospitalized between March 1998 and April 1999
throughout the country found that men who were on longterm
(defined as >1 yr) warfarin therapy were 63% more likely
to suffer an osteoporosis-related fracture of the hip, spine,
or wrist.Women on long-term therapy and patients who took
the drug for <1 year had no significant increase in risk.

Vitamin K is involved in the activation of bone proteins.
Warfarin's inhibition of this activation process because of
vitamin K antagonism may explain why patients on long-term therapy face an
increased risk of osteoporosis. The study also found that patients who were on
beta-blockers or who had high dietary intake of vitamin K and folate had a
decreased risk of fractures.